Elevator Car Guide-Rail Friction Module for Bounce Control
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Solution Overview
Problem
Elevator cars experience transient vertical vibration, or bouncing, during passenger boarding and alighting, leading to passenger discomfort and requiring costly and time-consuming structural modifications to mitigate.
Innovation Solution
A bouncing reduction device with a friction module and friction drive unit that generates frictional force against the guide rail, controlled by a PWM method, to reduce bouncing and noise, and is easily retrofitted without structural changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a friction module is pressed against the guide rail to generate frictional force, then bouncing is reduced, but noise is generated from contact between the friction body and the guide rail
Solution Approach 1:
The friction drive unit operates periodically by activating and deactivating the electromagnetic actuator in response to door open/close signals. This periodic activation maintains the friction module pressed against the guide rail during door operations (when bouncing occurs) while allowing it to disengage during other operations, reducing continuous noise generation while maintaining bouncing reduction effectiveness.
Solution Approach 2:
The electromagnetic actuator's pressing force is controlled by changing the duty cycle of PWM signals. By adjusting the duty cycle, the system optimizes the pressing force to generate sufficient frictional force for bouncing reduction while minimizing excessive force that would cause noise and wear. The control unit dynamically adjusts this parameter based on operational state.
2Stability of the object's composition
If the friction drive unit is continuously activated to maintain frictional force, then bouncing is continuously reduced, but energy is wasted and operational precision is compromised
Solution Approach 1:
The friction drive unit is activated periodically based on door open/close signals rather than continuously. The electromagnetic actuator is turned on when doors are opening or closing (when bouncing is likely to occur) and turned off when doors are closed or the elevator is moving, significantly reducing energy consumption while maintaining bouncing reduction effectiveness during critical periods.
Solution Approach 2:
The control unit receives door open/close signals as feedback and uses this information to determine when to activate the friction drive unit. This feedback mechanism ensures the system operates only when necessary, optimizing energy efficiency while maintaining bouncing reduction performance during door operations.
3Force
If the friction body is firmly pressed against the guide rail, then frictional force is maximized, but the friction body may displace or transfer shear loads causing failure
Solution Approach 1:
The friction drive unit uses an electromagnetic actuator that can dynamically adjust its pressing force. The actuator is designed to apply sufficient force to maximize frictional force for bouncing reduction, but the force is controlled through PWM duty cycle adjustment to prevent excessive force that would cause displacement or shear load transfer. The system dynamically balances these requirements based on operational needs.
4Stability of the object's composition
If structural modifications are made to the elevator system to reduce bouncing, then bouncing is reduced, but installation time and cost increase
Solution Approach 1:
The bouncing reduction function is segmented into a separate, modular friction module that can be independently installed on existing elevator guide rails. This modular approach allows the friction module to be added as a standalone component without requiring structural modifications to the main elevator system, significantly simplifying installation and reducing both time and cost.
Solution Approach 2:
The friction module acts as an intermediary component between the elevator car and the guide rail system. It provides the bouncing reduction function through frictional contact with the existing guide rail, serving as a mediator that improves performance without requiring fundamental changes to the elevator's structural system. This intermediary approach enables easy retrofitting on existing elevators.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces bouncing and noise while ensuring operational safety and stability, with precise control based on elevator states, and facilitates easy installation on existing systems.
Implementation Method 1
a friction module configured to be pressed against a guide rail while an elevator car is stopped at a floor, thereby reducing bouncing experienced by the elevator during boarding and alighting of passengers using frictional force generated between the friction module and the guide rail
Implementation Method 2
an electromagnetic actuator coupled to the friction module and configured to generate electromagnetic force in a direction toward the guide rail upon activation
Data Source
AI summary
Disclosed is a bouncing reduction device for elevator cars. The bouncing reduction device for elevator cars includes a friction module configured to be pressed against a guide rail while an elevator car is stopped at a floor, thereby reducing bouncing experienced by the elevator during boarding and alighting of passengers using frictional force generated between the friction module and the guide rail, can reduce noise from contact between a friction body and the guide rail while maximizing frictional force therebetween by adjusting the moving speed and pressing force of the friction body through control of a friction drive unit by a PWM control method, thereby ensuring improved overall performance and quality, and can be easily retrofitted to existing elevator cars without any structural modifications.